Species richness and functional structure of fish assemblages in three freshwater habitats: effects of environmental factors and management

Abstract

In this study, the inverted trophic hypothesis was tested in the freshwater fish communities of a reservoir. The distribution of fish species in three freshwater habitats in the Jurumirim Reservoir, Brazil, was examined using both species richness and the relative proportions of different trophic groups. These groups were used as a proxy for functional structure in an attempt to test the ability of these measures to assess fish diversity. Assemblage structures were first described using non‐metric multidimensional scaling (NMDS). The influence of environmental conditions for multiple fish assemblage response variables (richness, total abundance and abundance per trophic group) was tested using generalised linear mixed models (GLMM). The metric typically employed to describe diversity; that is, species richness, was not related to environmental conditions. However, absolute species abundance was relatively well explained with up to 54% of the variation in the observed data accounted for. Differences in the dominance of trophic groups were most apparent in response to the presence of introduced fish species: the iliophagous and piscivorous trophic groups were positively associated, while detritivores and herbivores were negatively associated, with the alien species. This suggests that monitoring functional diversity might be more valuable than species diversity for assessing effects of disturbances and managements policies on the fish community.

Ichthyofauna of the Marimbondinho River, Furnas Reservoir, Minas Gerais, Brazil

“…The data presented here indicate that the ichthyofaunistic richness of the sampled sites is lower than expected for dammed environments, where between 40 and 50 species were found by other authors (e.g., Pelicice et al 2018, Nobile et al 2019b, Queiroz-Sousa et al 2019). However, it is important to point out that the use of gillnets may have exerted sample selectivity on the ichthyofauna, preventing, for instance, the capture of small-sized species, such as those of the Poeciliidae and Characidae family.…”

Reservoir fish assemblage structure across an aquatic ecotone: Can river‐reservoir interfaces provide conservation and management opportunities?

“…There is a need to further understand mechanisms governing species distributions and potential interactions in river‐reservoir systems where native and non‐native species co‐occur (Clarkson, Marsh, Stefferud, & Stefferud, 2005; Gido et al., 2002; Oliveira, Minte‐Vera, & Goulart, 2005). For instance, species introductions into reservoirs have coincided with declines in native fish density and richness (Pelicice & Agostinho, 2009; Queiroz‐Sousa et al., 2019), but habitat complexity and turbidity associated with reservoir inflows might mediate negative species interactions, such as predation (Albrecht et al., 2010, 2018).…”

Knowing biodiversity: Fishes from the Guareí River basin, a tributary of the Jurumirim reservoir, Paranapanema River, Brazil

“…The Jurumirim Reservoir, in particular, has been investigated by multiple studies concerning its aquatic fauna (e.g., Panarelli et al 2001;Sartori et al 2009), including fish (e.g., Castro et al 2003a;Lima et al 2016;Lima et al 2018;Queiroz-Sousa et al 2019). Some studies (e.g., Seabra et al 2012;Nobile et al 2019) provided information about fishes in tributaries that flow into the Jurumirim Reservoir, such as the Taquarí and Guareí rivers.…”